#header{
    text-align: center;
    height:5rem;
    line-height: 5rem;
    font-size: 1.8rem;
    background: rgba(0,0, 0, 0.8);
    color: white;
    position: fixed;
    top: 0;
    width: 100%;
}
#header a{
    color: inherit;
}
#header .iconfanhui{
    position: absolute;
    left: 2rem;
    cursor: pointer;
}